The present invention relates to crop transport vanes and agricultural threshing and separating chambers employing them.
The time the crop resides in the threshing and separation chamber of a modern agricultural combine determines (mainly) the threshing losses, the straw breakage and the MOG (matter other than grain) separation to the cleaning system but also the power consumption. Different threshing conditions (tough wet crop vs. dry brittle crop) would benefit from different residence time in the threshing area in particular, to minimize grain loss, power consumption, etc.
On many modern combines, crop transport vanes are used to make sure the crop is transported to the back of the machine with desired residence times. Theses vanes, in combination with rotor elements (rasp bars, agitator pins, paddles, etc.) together with the rotor speed and crop properties like humidity, length of the straw determine the time the crop resides in the rotors. The current position and height of the vanes on the rotor covers are based on experience and must be seen as an average result for different crops and harvest conditions. In current machines, the height of the vanes is static, determined and set at the time of manufacture and installation. The angle of the vanes, in some instances is adjustable, although with some difficulty.
In some current embodiments, crop transport vanes are constructed from a rolled stainless steel angle. The vanes are bolted in place to a cylindrical housing in a helical arrangement to facilitate moving crops through the threshing chamber. The helical cage vane typically has three positions in which the vane can be bolted in place at three bolt locations on each vane to provide varying material transport speeds. By altering the angle of the vane relative to the direction of crop flow, crop flow can be sped up or slowed down as desired. The curvature from the helical shape of the vane does not conform well to each of the three different angular positions within the tubular threshing chamber. Thus, when adjusted the vane often does not mate well with the curvature of the threshing chamber; extra force or tightening of the bolts is required to force the vane into proper curvature. Each vane needs to be individually adjusted and secured with three bolts.
U.S. Pat. No. 4,244,380 recognizes the tediousness of adjusting each vane and proposes an apparatus whereby a single lever can adjust the angular positioning of the vanes. The '380 patent also recognizes that the vanes, once repositioned, no longer conform to the inner curvature of the rotor cover and that it is necessary to tighten the nuts and bolts to draw the vanes into a configuration corresponding to the curvature of the threshing chamber. Thus, while the '380 device addresses the simultaneous adjustment of the angle of the vanes, it still requires first loosening each of three bolts on each vane and then retightening those bolts upon readjustment to maintain the appropriate curvature.
These adjustments, even in the improved design take valuable time. Accordingly, more and better ways of adjusting the crop transport speed within the threshing chamber are sought after. Applicants have invented just that.